In general, a ceramic resistor or a fuse for protecting a power circuit is installed on a power input terminal of an electric circuit of an electronic product to prevent malfunction of devices caused by inrush current, increase of internal temperature or continuous over current occurring when the electronic product is powered on. However, since large-size electronic appliances, such as an LCD TV and a PDP TV, use high power of 200 W or above, the conventional ceramic resistor or the conventional fuse may not effectively solve the malfunction of devices. Thus, a new protective device called a thermal fuse resistor has been developed and used.
The conventional fuse resistor includes a resistor and a thermal fuse which are connected to each other in series. When inrush current is introduced into the electronic product, the resistor restricts the inrush current to the level of predetermined current. In addition, when over current is introduced into the electronic product, a fusible member made from solid-phase lead or a polymer pallet and provided in the thermal fuse is melted by heat generated from the resistor, thereby disconnecting the circuit.
In addition, according to the conventional fuse resistor, the resistor and the thermal fuse are packaged in a case to protect electronic parts from being damaged by particles generated when the fusible member is melted, and fillers, such as SiO2, are filled in the case to improve the heat-resistant, conductive and curing properties.